Power steering apparatus for a vehicle

ABSTRACT

A power steering apparatus in which an oil pump is selectively connected to opposite chambers of a power steering cylinder by an operation valve driven by a steering handle. The operation valve comprises a rotary disk enclosed in a valve chamber having supply and return lines in one side surface thereof, the disk having fluid conducting openings in the form of through bores to connect the supply and return lines together in a neutral steering position, and to connect them respectively to the opposite chambers in the power steering cylinder in right and left steering positions. The opposite side surface of the valve chamber is formed with areas on which the oil acts which are symmetrical with the supply and return openings at the other side of the valve chamber and these areas are in communication with the supply and return openings via through bores in the rotary disk.

United States Patent 1 1 1111 3,735,232 Akima 1 May 29, 11973 883,65412/1961 Great Britain ..l80/79.2 R

A VEHICLE Inventor: Akira Akima, Tokyo, Japan Honda Giken- KogyoKabushiki Kaisha, Japan Mar. 2, 1971 Assignee:

Filed:

Appl. No.:

Foreign Application Priority Data References Cited UNITED STATES PATENTSVerbrugge et a1. "180/792 R Suzuki et a1. "91/375 X FOREIGN PATENTS 0RAPPLICATIONS 3/1965" Canada..... ..l80/79.2R

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Primary Examiner-Kenneth H. Betts Assistant Examiner--Leslie J. PapernerAttorney-Waters, Roditi, Schwartz & N issen ABSTRACT A power steeringapparatus in which an oil pump is selectively connected to oppositechambers of a power steering cylinder by an operation valve driven by asteering handle. The operation valve comprises a rotary disk enclosed ina valve chamber having supply and return lines in one side surfacethereof, the disk having fluid conducting openings in the form ofthrough bores to connect the supply and return lines together in aneutral steering position, and to connect them respectively to theopposite chambers in the power-steering cylinder in right and leftsteering positions. The opposite side surface of the valye chamber isformed with areas on which the oil acts which are symmetrical with thesupply and return openings at the other side of the valve chamber andthese areas are in communication with the supply and return openings viathrough bores in the rotary disk.

1 Claim, Drawing Figures lwmll.

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SHEET 3 OF 3 INVENTOR POWER STEERING APPARATUS FOR A VEHICLE BRIEFSUMMARY OF THE INVENTION This invention relates to power steeringapparatus in vehicles such as motorcars or the like of the type in whichan oil pump is selectively connected to opposite end chambers of a powersteering cylinder through an operation valve controlled by a steeringhandle.

An object of the invention is to provide such a steering apparatuswherein the operation valve is of rotary type so that the apparatus canbe of small size and reliable in valve operation and yet be smooth andlight in handling.

According to this invention, in a power steering apparatus'of the typein which an oil pump is selectively connected to either of opposite endchambers of a power steering cylinder through'an operation valve drivenby a steering handle, the operation valve is formed as a rotary diskcontained in a valve chamber having oil supply and on return openings inone side surface thereof, oil conducting openings being prodisk.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic illustrationshowing a ne'utral condition of power steering apparatus according tothis invention, and partly in section as taken along line I I in FIG. 2;

FIG. 2 is a sectional view taken along line II II in FIG. 1;

FIG. 3 is a sectional view taken along line III III in FIG. 2;

FIG. 4-is a sectional view taken along the line IIlI- -IIII in FIGS andshows the power steering apparatus in position for a right turn;

FIG. 5 is a sectional view taken along line V V in FIG. 4; a

FIG. 6 is a sectional view taken along line VI VI in FIG. 7,and showsthe power steering apparatus in position for a left turn; and

FIG. 7 is a sectional view taken along line VII VII in FIG. 6.

DETAILED I DESCRIPTION Referring to the drawing, numeral 1 denotes acasing ofa valve control for a power steering apparatus, and mounted inthe casing at opposite ends thereof are an input shaft 2 connected to asteering handle 20 and an output shaft-3 connected to a steering rack3a. The shafts 2 and 3 are inserted in the casing l at the front andrear thereof, respectively, so as to be in alignment with one another,and the shafts 2 and 3 are connected together through a torsion bar, sothat a relative angular deflection can exist between the two shafts 2and 3 when a torque is applied therebetween. A valve body 5 is securedto the output shaft 3 at its inner end and the valve body serves'forreceiving and delivering an operating fluid, such as oil. Numeral 6denotes a valve chamber formed in the valve body 5. A rotary disk 7 isintegrally formed with the input shaft 2 at its inner end, and the disk7 is in the form of a flange. The disk 7 is rotatably enclosed in thevalve chamber 6. A pair of oil supply passages 10 are in communicationwith an oil pump 9 having an oil reservoir 8, the passages 10 beingformed in the valve body 5 such that they have larger diameter cavities11 at their front ends which open to one side surface of the valvechamber 6 so as to be arranged at two diametrically opposed positionswhich are symmetrical with one another. A pair of oil return passages 12are in communication with the oil reservoir 8 and are also formed in thevalve body 5 with larger diameter cavities 13 at their front ends whichopen at the same side surface of the valve chamber 6 so as to bedisposed between the cavities 11. The cavities 13 are diametricallyopposed to one another along a diameter at right angles to the diameteralong which cavities .11 are aligned. Additionally provided are a pairof oil delivery passages 17 and a pair of oil delivery passages 18. Thepassages 17 are in communication with one end chamber 15 of a powercylinder 16, and the passages 18 are in communication with the other endchamber 16 of the power cylinder 14. The passages 17 and 18 arealsoformed in the valve body 5 such that they are open at their frontopen ends in the same side surface of the valve chamber 6 so as to bedisposed at four positions each being between adjacent cavities 11 and13.

The rotary disk 7 is provided at four positions, each of whichcorresponds to an intermediate position of the adjacent cavities 11 and13 with four oil conducting openings 19, 20, 21 and 22, and each ofthese openings 19, 20, 21 and 22 is formed as a bore passing through therotary disk 7 and having substantially the same diameter as that of eachof the cavities l1 and 13. The openings 19, 20, 21 and 22 are soarranged that, at a neutral position as shown in FIGS. 1 and 2, eachthereof partly overlaps and is in communication with the opposite sidecavities 11 and 13, so that in this condition the oil supplied from theoil pump 9 flows from each cavity 11 connected to each oil supplypassage 10 to the opposite oil conducting openings 19, 22 and 20, 21,respectively, and thence through each cavity 13 and each oil returnpassage 12 to return to the oil reservoir 9. Thus the oil does not flowinto the power cylinder 14.

If the rotary disk 7 is given a right turning movement through the inputshaft 2, as shown in FIGS. 4 and 5, each cavity 11 overlaps only the oilconducting opening 20 or 22, so that the oil supplied from each oilsupply passage 10 flows from the oil conducting openings 21) and 22,respectively, and through the respective oil delivery passages 17 intoend chamber 15 of the power cylinder 14, and thus the power cylinder Mis operated.

If, however, the rotary disk 7 is given a left turning movement throughthe input shaft 2, as shown in FIGS. 6 and 7, each cavity 11 overlapsonly the oil conducting opening 29 or 21, so that the oil supplied fromeach oil supply passage 10 flows from the oil conducting openings 19 and21, respectively and through the respective oil delivery passages 18into the chamber 16 of the power cylinder 14, and thus the powercylinder 16 is operated.

The oil conducting openings 19, 20, 21 and 22 in the rotary disk 7 areformed as through bores in the disk '7,

so that it can be prevented that the oil pressure acts only on one sidesurface of the rotary disk 7 to cause resistance against rotary movementthereof.

Though the oil supply and oil return passages 10 and 12 are arranged toface one side surface of the rotary disk 7 at their end cavities 11 and13 as mentioned before, at the position corresponding to these cavitiesl1 and 13, according to the invention, respective bores 23 are made inthe rotary disk 7 and respective circular cavities 24 are made in theopposite side surface of the valve chamber 6 so as to be incommunication with the bores 23. Thus, surfaces are formed on both sidesof rotary disk 7 on which the oil pressure acts and these surfaces areidentical so the forces are equal for balancing the oil pressuresapplied to the opposite side surfaces of the rotary disk 7 and thus itcan be prevented that the oil pressure serves as a resistance againstrotation of the rotary disk 7.

It is preferable that each of the openings 19, 20, 21, 22 and 23 in therotary disk 6 be circular as illustrated, whereby the manufacture of therotary disk can be simplified and facilitated.

Thus, according to this invention, in a steering apparatus of the typein which an oil pump is selectively connected to opposite end chambersof a power steering cylinder through an operation valve driven by asteering handle, the operation valve is of rotary type and comprises arotary disk contained in a valve chamher, and oil supply and oil returnopenings for the valve are all made only in one side surface of thevalve chamber, so that these openings can be concentrated on one sideand the whole of the apparatus can be of small size. Additionally, oilconducting openings made in the rotary disk for communicating betweenthe oil supply and oil return openings are formed-as bores passingthrough the rotary disk, so that it can be prevented that oil pressureis applied to only one side surface of the rotary disk. Furthermore, theend openings of the oil supply and oil return passages open to therotary disk constitute an area on which oil pressure acts on the rotarydisk, but according to this invention another oil pressure areasubstantially equal to the foregoing oil pressure acting area is formedon the other side surface of the rotary disk and these two areas are incommunication with each other through communication openings forbalancing the oil pressure applied to the opposite side surfaces of therotatable disk, to eliminate any oil pressure resistance against therotation of the rotary disk whereby the handling of the apparatus can besmooth and light.

What is claimed is:

1. Power steering apparatus for a vehicle comprising a fluid pump, apower steering cylinder having a piston with chambers on opposite sidesthereof, an operation valve driven by a steering handle and regulatingflow from the pump to said chambers to effect corresponding steering ofthe vehicle, said operation valve comprising a rotary disk enclosed in avalve chamber having fluid supply and fluid return openings in one sidesurface thereof, said disk having fluid conducting openingscommunicating the fluid supply and return openings in a neutral steeringposition, and respectively connecting the supply and return openingswith said chambers of said power steering cylinder in left and rightsteering positions, said conducting openings being through bores passingthrough the rotary disk, said valve chamber having an opposite sidesurface on the other side of said rotary disk, which opposite sidesurface is provided with openings which are symmetrical with said supplyand return openings and have the same areas there as to balance forcesacting on opposite sides of said disk, said disk having further circularbores therein providing communication between said supply and returnopenings and the symmetrical openings in the opposite side surface ofthe valve chamber, said supply and return openings having enlargeddiameters where they open into said valve chamber, said openings in saidopposite side surface of the valve chamber being equal in diameter tothe enlarged diameters of the supply and return openings, said supplyand return openings being grouped in diametrically opposed pairs atright angles to one another, said fluid conducting bores in said diskhaving the same diameter as the enlarged diameters of the supply andreturn openings and in said neutral steering position overlap saidopenings whereby fluid passes from the supply to the return openingswithout passing to the power steering cylinder, said fluid conductingbores being also grouped in diametrically opposed pairs at right anglesto one another, said further bores communicating the supply and returnopenings with the symmetrical openings in the opposite side surface ofthe valve chamber are disposed between respective fluid conductig bores,and said openings in said opposite side surface of the valve chamberbein constituted as circular cavities.

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1. Power steering apparatus for a vehicle comprising a fluid pump, a power steering cylinder having a piston with chambers on opposite sides thereof, an operation valve driven by a steering handle and regulating flow from the pump to said chambers to effect corresponding steering of the vehicle, said operation valve comprising a rotary disk enclosed in a valve chamber having fluid supply and fluid return openings in one side surface thereof, said disk having fluid conducting openings communicating the fluid supply and return openings in a neutral steering position, and respectively connecting the supply and return openings with said chambers of said power steering cylinder in left and right steering positions, said conducting openings being through bores passing through the rotary disk, said valve chamber having an opposite side surface on the other side of said rotary disk, which opposite side surface is provided with openings which are symmetrical with said supply and return openings and have the same areas there as to balance forces acting on opposite sides of said disk, said disk having further circular bores therein providing communication between said supply and return openings and the symmetrical opeNings in the opposite side surface of the valve chamber, said supply and return openings having enlarged diameters where they open into said valve chamber, said openings in said opposite side surface of the valve chamber being equal in diameter to the enlarged diameters of the supply and return openings, said supply and return openings being grouped in diametrically opposed pairs at right angles to one another, said fluid conducting bores in said disk having the same diameter as the enlarged diameters of the supply and return openings and in said neutral steering position overlap said openings whereby fluid passes from the supply to the return openings without passing to the power steering cylinder, said fluid conducting bores being also grouped in diametrically opposed pairs at right angles to one another, said further bores communicating the supply and return openings with the symmetrical openings in the opposite side surface of the valve chamber are disposed between respective fluid conducting bores, and said openings in said opposite side surface of the valve chamber being constituted as circular cavities. 